Momentum hammer with a handle carried slidable weight



Feb. 14, 1967 w. M. TITCHNELL 3,303,863

MOMENTUM HAMMER WITH A HANDLE CARRIED SLIDABLE WEIGHT Filed July 9, 1965INVENTOR.

WILLIAM M. T/TCHNELL BY MAHoyEY, MILLER a RAMBO A TORN E YS UnitedStates Patent 3,303,863 MOMENTUM HAMMER WITH A HANDLE CARREED SLIDABLEWEIGHT William M. Titchnell, R0. Box 27066, Columbus, Ohio 43277 FiledJuly 9, 1965, Ser. No. 470,817 6 Claims. (Cl. 145-29) My inventionrelates to a momentum hammer. It rel-ates to a lightweight, hand-typehammer provided with means for automatically increasing the momentumduring the swinging of the hammer and just prior to striking a blowthereby producing an increased impact with less strain, fatigue andshock on the hand and arm of the user.

With the ordinary hammer or similar hand tool, the center of mass is ator very near the hammer head, thus creating a large moment to berestrained by the hand and arm muscles except during the actual strikingof the blow with the hammer. The hammer of the present invention has itscenter of mass considerably farther down the handle away from the hammerhead, as compared with the usual hammer, during most of the swing towardimpact, giving a more comfortable feeling in the hand and arms of theuser, but is provided with means for automatically increasing the massof the head as it nears impact. The increase in mass at the headprovides a greatly increased moment to thereby greatly increase thestriking force at impact. It is preferred that the means for increasingthe mass of the hammer head at impact be a shiftable weight, forexample, a ball, which is mounted in a guide passage extending along thehandle from a point adjacent its end to a location within the hammerhead. Means is provided at the end of the handle for normallyrestraining movement of the weight until sufficient centrifugal force isdeveloped by the swing of the hammer toward impact to move the weightinto the hammer head. This will result in an increase in mass .in thehammer head and greater impact at the time it is needed but a decreasein weight and mass at other times to thereby decrease strain andresulting fatigue on the user.

In the accompanying drawing, I have illustrated my invention embodied ina hammer of the type used for driving nails and similar work but is tobe understood that the same principles may be incorporated in any handtool or device which has a handle and a head and which is to be swung bythe handle during use. For example, the invention may be incorporated inother items, such as mallets, axes, golf clubs, etc.

In the drawing:

FIGURE 1 is a longitudinal sectional view through the hammer.

FIGURE 1a is a similar sectional view of the head of the hammer showingthe moment-increasing ball located in the head.

FIGURE 2 is a head-end elevational view taken from the positionindicated at line 2-2 of FIGURE 1.

FIGURE 3 is an enlarged transverse sectional view taken through thehammer handle.

\Vit'h reference to the drawing, as indicated above, in the exampleshown, the tool is a hammer which comprises mainly a handle having ahead 11. The head and handle are shown as being integral but may beformed separately and suitably connected. Also, the specific shape ofhead and handle is not important to the invention and can be varied.

The handle 10 is shown in the form of a hollow tube which has its outersurface of a contour to properly fit the hand and has a guide passage 12of circular cross section extending its full length. In forming thepassage 12, it may be formed with both ends open to facilitate itsformation, with the ends later closed by means indicated and which willbe described. The head 11 may be provided with a replaceable impact knob13 which may be mounted on the head itself by a screw and socketarrangement as indicated at 14.

Within the passage 12, for automatic movement therealong, I haveprovided a shiftable Weight 15. This weight is shown as a ball which ismagnetic for a purpose which will -be apparent later and is of steel orother magnetic material. The ball is of a diameter just slightly lessthan the internal diameter of the passage 12 so that it will fit snuglytherein. The end of the passage 12, at the end of the handle, is closedby a removable permanent magnet 16 of disc-like form which is screwedinto a threaded socket at the extremity of the passage 12. When the ball15 moves or rolls to the end of the handle 10 in the passage 12, it willcontact the magnet 16 and be retained in that position until themagnetic force is overcome. To aid in retaining it in that position, theside of the passage 12 is provided with a hemispherical slot or socket17 extending radially outwardly into the inner surface thereof. Thissocket is of greater diameter than the diameter of the ball 15 and willreceive the ball when the ball moves to the end of the handle. It willbe noted that the axis of the socket 17 is in a plane common with theaxis of the passage 12 and the impact member 13 and extends radially inthe direction of the member 13.

The passage 12, as indicated, extends into the head 11 and this end ofthe passage is closed by a removable cap 18 of disc-like form which isscrewed into the threaded outer end of a socket 19 -at the end of thepassage. A disc 20 is mounted for axial movement in the socket 19 and isnormally biased inwardly against an annular stop shoulder 21 by means ofa compression spring 22 disposed between the disc members 18 and 20.Immediately axially inwardly of the stop shoulder 2-1 preferably thereis provided an annular enlargement 23 which forms an annular chamberthat communicates with the passage 12. The wall surfaces of this chamberis preferably curved spherically substantially complemental to thesurface curvature of the ball 15. The inwardly springpressed disc 20provides a ball movement cushioning and return plunger arrangement whichwill function in a manner to be described below. If desired, the passage12 and connected chamber 23 may be filled with a viscous fluid whichwill dampen movement of the ball 15 and dampen out shock or a dashpot(not shown) may 'be operatively connected in series with the spring 22.

Assuming the hammer handle 10 is grapsed by the user, and the handle isvertical or is tilted rearwardly and downwardly toward the user with theend of the hammer lower than the head 11, the weight ball 15 will be inthe end of the handle in the socket 17 at the position indicated by fulllines in FIGURE 1. In swinging the hammer head 11 toward the article tobe struck, the ball 15 will stay in the indicated position, untilsufiicient centrifugal force is developed to overcome the magneticretaining force and to c ause the ball to ride up out of the socket 17.The ball will then quickly move through the passage 12 until it strikesthe contact button 20 which will cushion its impact and as the contactmember 13 moves toward impact, the ball will move .into the side of theannular chamber 23 away from that member, as indicated in FIGURE 1a.This will increase the mass of the hammer head just prior to and at thetime of impact to thereby give a more effective blow. The spring 22 willcushion the movement of the ball as it reaches the head and will becompressed to some extent at this time by contact of the ball 15 withthe disc 20. At impact. the ball 15 will tend to quickly move to theopposite side of the chamber 23 and exert -a dampening effect on therebound of the hammer head 11 resulting from impact.

a As the hammer head rises after the blow, the tendency of the ball toroll from the chamber 23 into the main part of the passage 12 will beaided by the biasing effect of the spring 22. The ball will continue tomove along the guide passage 12, as the head of the hammer is raised toa greater extent, and will move downwardly until it reaches the end ofthe handle and is retained in that position by contact with the magnet16.

With this arrangement, the momentum-increasing weight does not move intothe head 11 of the hammer until sufiicient centrifugal force isdeveloped, during the swing toward impact, to overcome theweight-retaining force of the magnet 16. The weight, in the form of thesteel ball 15, releases from the permanent magnet 16 due to the increaseof the g force to overcome the force of the magnet which results fromthe swinging of the hammer toward impact. Upon completion of the swing,the ball is in the chamber 23 at the instant of impact, thus giving thehammer head its full mass to simulate the tangential force of aconventionally constructed hammer with a heavier head. Upon impact, themovement of the ball in the chamber 23, toward the impact side, cushionsthe rebound of the hammer head and the spring-biased ball contactingdisc tends to exert a force on the ball which will deflect it in thepassage 12 toward the magnet 16. At the upper return portion of thehammer swing, the ball 15 is back at the magnet 16 and the process isrepeated with each subsequent swing. The hemispherical socket 17 isutilized to keep the steel ball 15 from moving forward during aiming orback swings of the handle and the ball will be positioned therein eachtime it moves into the rear end of the handle in contact with the magnet16, On back swings, g forces keep the ball in the socket and keepcentrifugal force from forcing the ball toward the head.

As previously indicated, my invention is not limited to a hammer but maybe incorporated in any device comprising an impact head and a connectedhandle for swinging it through a working arc, with the movable weightbeing so carried by the handle that will move into the headautomatically as it is swung towards impact to thereby increase theweight and inertia of the head at impact.

According to the provisions of the patent statutes, the principles ofthis invention have been explained and have been illustrated anddescribed in what is now considered to represent the best embodiment.However, it .is to be understood, that, within the scope of the appendedclaims, the invention may be practiced otherwise than as specificallyillustrated and described.

Having thus described this invention, what is claimed 1. An i mpactapplying device comprising an impact head, a handle connected to thehead for swinging it into an impact position, a weight mounted on thehandle for movement from a position along the handle remote from thehead to a position at the head to increase the weight of the head as itis swung by the handle toward impact, and means for retaining the weightin said remote position until a predetermined centrifugal force isdeveloped during swinging of the head toward impact.

2. An impact-applying device comprising an impact head, a handleconnected to the head for swinging it into an impact position, saidhandle being provided with a guide passage extending therealong from aremote position to a position in the head, a weight mounted in saidguide passage for movement between said remote position and the head,and means adjacent said remote position of the passage for exerting aretaining force on said weight which can be overcome by centrifugalforce developed by swinging of the head with said handle toward impact.

3. An impact-applying device comprising an impact head, a handleconnected to the head and extending therefrom to a remote end forswinging it to and from impact position, said handle being provided witha guide passage communicating with a chamber in said head and extendingalong the handle to the remote end of the handle, a ball weight ofmagnetic material mounted in said passage for movement therealong andinto and out of said chamber, and a magnet at the remote end of thehandle for normally retaining said ball at said remote end of handle.

4. A device according to claim 3 in which said passage has aball-receiving socket in the wall thereof adjacent said remote end ofthe handle.

5. A device according to claim 3 in which said chamber in said head is acontinuation of said passage and is provided with a spring-biasedplunger with which said ball will engage when it moves into said head.

6. A device according to claim 3 including means acting on the ball insaid chamber for deflecting it in said passage toward the magnet at theremote end of the handle after impact.

References Cited by the Examiner UNITED STATES PATENTS 7/ 1952 K-ahlen.8/1961 Yearley.

1. AN IMPACT-APPLYING DEVICE COMPRISING AN IMPACT HEAD, A HANDLECONNECTED TO THE HEAD FOR SWINGING IT INTO AN IMPACT POSITION, A WEIGHTMOUNTED ON THE HANDLE FOR MOVEMENT FROM A POSITION ALONG THE HANDLEREMOTE FROM THE HEAD TO A POSITION AT THE HEAD TO INCREASE THE WEIGHT OFTHE HEAD AS IT IS SWUNG BY THE HANDLE TOWARD IMPACT, AND MEANS FORRETAINING THE WEIGHT IN SAID REMOTE POSITION UNTIL A PREDETERMINEDCENTRIFUGAL FORCE IS DEVELOPED DURING SWINGING OF THE HEAD TOWARDIMPACT.